Hydro-legs for boats



April 11, 1967 D. R. DAVIS 331mm HYDRO LEGS FOR BOATS Filed Aug. 2, 1965 DAV/D P. a DAWS INVENTOR.

United States Patent 3,313,261 HYDRO-LEGS F012 BOATS David R. Davis, Beverly Hills, Calif, assignor to V and W Aircraft Castings, Inc, Bell Gardens, Calif. Filed Aug. 2, 1965, Ser. No. 476,518 2 Claims. (Cl. 114-665) This invention relates to hydro-legs for boats, to increase the speed of the boat.

It is well known in the design of high speed boats that the performance of such a craft can be improved with the use of hydrofoils which function from a position under the water to lift the craft above the water to reduce its drag and increase its speed. Hydrofoils are attached to boats by struts which hold them in position under the water. These struts and attachments drag through the water to decrease the speed. I have discovered that hydrofoils are not required to lift the boat from the water and that the struts themselves will function as hydro-legs to accomplish this purpose if they extend downwardly and rearwardly from the hull of the boat to penetrate the water at an angle which is less than 30 degrees from the surface level of the Water.

Hydro-legs functon to advantage in many ways which are not realized by hydrofoils. The deeper these sloping hydro-legs are immersed, the greater their lifting area becomes and the more their center of lift moves forward toward the bow of the boat, causing the hydro-leg boat to tend to ride a wave instead of plunging through it. Another advantage inherent to hydro-leg design is that they cannot strike floating objects head on but strike a glancing blow which tends to slide over floating objects to sink them and to ease the shock against the hydro-leg. Hydrofoils are particularly susceptible to damage caused by collisions with the floating debris.

The purpose of this invention is to provide a mechanism which will lift a boat out of the Water and increase its speed wherein all of the submerged parts of the mechanism slope rearwardly to intercept the water at an angle less than 30 degrees, to minimize the shock caused by impact with floating or under water debris.

Another purpose of this invention is to provide a speed boat with an underwater lifting mechanism which will gradually increase its lifting area as it submerges to greater depths and, at the same time, shift its center of lift gradually forward toward the bow of the boat.

A further purpose of this invention is to provide an underwater lifting mechanism for speed boats wherein all of the individual parts of said mechanism and its supports function to produce more lift than drag.

Other objects and many attendant advantages of this invention will be apparent as the invention is better understood by reference to the accompanying drawings and detailed descriptions.

FIG. 1 is a side elevational view of a craft utilizing a preferred embodiment of the invention and depicting the craft at rest with its hydro-legs retracted.

FIG. 2 is a side elevational view of the craft illustrated in FIG. 1 showing the craft under way with its hydrolegs extended.

FIG. 3 is a top plan view of the craft illustrated in FIG. 1 and FIG. 2.

FIG. 4 is a cross-sectional view taken at 4-4 of FIG. 1 through the pinion and rack assembly which functions to rotate shaft assembly 16a and 16b.

FIG. 5 illustrates a cross-sectional shape which can be used in a hydro-leg with the open end of the 'U heading down stream.

FIG. 6 is the cross-section of a tubular hydro-leg.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughice out the several views, there is shown in FIG. 1 a hull 14 adapted to be driven through the water by an outboard motor and propeller unit 11. Water level is indicated at '12 and hydro-legs 15 and 16 are shown in retracted 5 position alongside the hull with synchronizing spacer bar .17 rotatably pinned to hydro-legs 15 and 16 at pin points 18a and 18b. Section 4-4 intersects pinion and rack assembly 25, 26, 27, 28 and the center of scaled bearing 22. In FIG. 2 handle 27 has been moved forward to cause hydro-legs 15 and 16 to rotate into a position where they extend downwardly and rearwardly from the hull to penetrate the water at an angle of about 30 degrees from surface water level 12. In FIG. 2 the boat has been lifted out of the water by the water pressure under those portions of the hydro-legs which are immersed below water level. Spacer bar 17 has maintained hydro-legs 15 and 16 in parallel to assure that they penetrate the water at similar angles. FIG. 3 indicates that hydro-legs 15 and 16 have counterparts on the opposite side of the boat labelled 15b and 16b. These legs are connected to legs 15a and 16a by cross shafts 15'a and 15b and 16a and 16b, respectively. These shafts are mounted in bearings 22 to allow the hydrolegs to be rotated into functioning position in unison. 25 They may be separated at coupling 20 and removed by sliding through bearing 22.

It is evident that hydro-legs can be individually locked into functioning position when the boat is at rest and under this circumstance do not require spacer bars or connecting shafts or rack and pinion assemblies nor other synchronizing or retracting paraphernalia illustrated in the drawings of the preferred embodiment of the invention. It should also be understood that invention is not restricted to a boat with 4 hydro-legs but that any number of hydro-legs may be used, and that they do not have to be straight nor have the same cross-section thoughout their length so long as their wetted portions are swept back to maintain an angle of attack which is less than 30 degrees to the water level. It is also evident that other propulsion means may be employed to propel the boat and that this patent is not limited to boats with outboard motors. I

What is claimed is:

4 1. A boat having at least two hydro-legs in tandem mounted on its hull on one side of the longitudinal axis of said hull, and at least two hydro-legs in tandem mounted on said hull on the opposite side of said longitudinal axis; and means for positioning said hydro-legs in a downward and rearwardly extending direction into the water to a depth greater than the boats draft and at an angle less than 30 from the water level, the portion of each of said hydro-legs extending into the water consisting solely of a single elongated member lying generally in a vertical plane.

2. A boat according to claim 1, in which said means includes intercoupling members maintaining said hydrole-gs intandem in parallel relationship to each other.

References Cited by the Examiner UNITED STATES PATENTS 1,750,959 3/1930 Lake 1 1466.5 2,991,746 7/1961 Cunningham 1 1466.S 3,168,067 2/1965 Graig 1l466.5

OTHER REFERENCES Hovering Craft & Hydrofoil, vol. 4, No. 8, May 1965, page 6.

MILTON BUCHLER, Primary Examiner. ANDREW H. FARRELL, Examiner. 

1. A BOAT HAVING AT LEAST TWO HYDRO-LEGS IN TANDEM MOUNTED ON ITS HULL ON ONE SIDE OF THE LONGITUDINAL AXIS OF SAID HULL, AND AT LEAST TWO HYDRO-LEGS IN TANDEM MOUNTED ON SAID HULL ON THE OPPOSITE SIDE OF SAID LONGITUDINAL AXIS; AND MEANS FOR POSITIONING SAID HYDRO-LEGS IN A DOWNWARD AND REARWARDLY EXTENDING DIRECTION INTO THE WATER TO A DEPTH GREATER THAN THE BOAT''S DRAFT AND AT AN ANGLE LESS THAN 30* FROM THE WATER LEVEL, THE PORTION OF EACH OF SAID HYDRO-LEGS EXTENDING INTO THE WATER CONSISTING SOLELY OF A SINGLE ELONGATED MEMBER LYING GENERALLY IN A VERTICAL PLANE. 